In recent years, there has been a worldwide demand to improve the fuel efficiency of automobiles in order to conserve the world's limited supply of petroleum based hydrocarbons.
Studies have indicated that a relatively large amount of the energy consumed by an automobile is used to overcome the rolling resistance of its tires, caused by hysteresis losses in the tire tread compounds. Therefore, automobile manufacturers have put rigid specifications on original equipment tires to reduce rolling loss by hysteresis, while maintaining treadwear resistance, traction, and handling characteristics. As these specifications become more and more demanding, the tire suppliers have asked their suppliers of polymers and carbon black, the two largest components in tires, to assist them by producing materials that will decrease hysteresis losses in tire tread compounds.
Carbon black producers have been active in trying to develop new grades of carbon black that impart good treadwear properties with decreased hysteresis properties, while maintaining satisfactory traction and handling characteristics. It has been found that changing the balance between treadwear and hysteresis properties of carbon black is very difficult to achieve by conventional manufacturing methods. In general, decreases in hysteresis values are accompanied by decreases in treadwear resistance, and vice versa.
In a carbon black reactor with a linear flow pattern (see FIG. 1), it is customary to inject carbon black feedstock oil through multiple hydraulic spray nozzles into a hot combustion gas stream emanating from a combustion zone located upstream of the carbon black feedstock oil injection point. It is further customary to inject the atomized carbon black feedstock oil radially inwardly and/or outwardly at essentially a right angle to the direction of flow of the hot combustion gas stream, in order to disperse the feedstock oil uniformly into the hot combustion gas stream. The total flow of carbon black feedstock oil is metered as a single stream even though this stream is subdivided into multiple streams for injection into the hot combustion gas stream.
Patently the foregoing techniques utilizing the reactors currently employed do not provide carbon black products with the aforedescribed desiderata.